Metered dose medicament inhalers are well known for dispensing medicament to the lungs of a patient. Some previous inhalers have comprised a pressurized aerosol dispensing container, wherein the aerosols contain gas propellants in which the powdered medicament is suspended. Upon actuation, the aerosol contents are expelled, through a metering valve, and into the lungs of the patient. However, it is now known that some aerosol propellants, including those used in metered dose inhalers, can cause depletion of the ozone layer in the atmosphere. In addition, such aerosol systems are not suitable for all patients.
Several types of non-aerosol, breath actuated dry powder inhalers have therefore been provided. For example, U.S. Pat. No. 5,503,144 to Bacon, which is assigned to the assignee of the present disclosure and incorporated herein by reference, shows a breath-actuated dry-powder inhaler. The device includes a dry powder reservoir for containing a dry powdered medicament, a metering chamber for removal of the powdered medicament from the reservoir in discrete amounts, and an air inlet for entraining the removed powdered medicament through a mouth piece upon patient inhalation.
Regardless of whether an aerosol or non-aerosol inhaler is used, it is of utmost importance that particles of the dispensed dry powder medicament be small enough to ensure the adequate penetration of the medicament into the bronchial region of a patient's lungs during inhalation. However, because the dry powder medicament is composed of very small particles, and often provided in a composition including a carrier such as lactose, non-defined agglomerates or aggregates of the medicament form at random prior to being dispensed. It has therefore been found preferably to provide breath-actuated dry powder inhalers with means for breaking down the agglomerates of medicament or medicament and carrier before inhalation of the medicament.
Accordingly, there is desired an improved dry powder inhaler and, in particular, an improved breath-actuated dry powder inhaler. There is also desired a de-agglomerator for a breath-actuated dry powder inhaler and method for breaking down agglomerates of medicament, or medicament and carrier, before inhalation of the medicament by a patient.